3 files changed, 104 insertions, 13 deletions
diff --git a/gr-digital/python/digital/ofdm_txrx.py b/gr-digital/python/digital/ofdm_txrx.py
index a48a48db41..76bf337b8d 100644
--- a/gr-digital/python/digital/ofdm_txrx.py
+++ b/gr-digital/python/digital/ofdm_txrx.py
@@ -145,7 +145,8 @@ class ofdm_tx(gr.hier_block2):
                  sync_word1=None,
                  sync_word2=None,
                  rolloff=0,
-                 debug_log=False
+                 debug_log=False,
+                 scramble_bits=False
                  ):
         gr.hier_block2.__init__(self, "ofdm_tx",
                     gr.io_signature(1, 1, gr.sizeof_char),
@@ -193,13 +194,32 @@ class ofdm_tx(gr.hier_block2):
         ### Payload modulation ###############################################
         payload_constellation = _get_constellation(bps_payload)
         payload_mod = digital.chunks_to_symbols_bc(payload_constellation.points())
+        if scramble_bits:
+            self.connect(
+                crc,
+                digital.additive_scrambler_bb(
+                    0x8a, 0x7f, 7,
+                    bits_per_byte=bps_payload,
+                    reset_tag_key=self.packet_length_tag_key
+                ),
+                blocks.repack_bits_bb(
+                    8, # Unpack 8 bits per byte
+                    bps_payload,
+                    self.packet_length_tag_key
+                ),
+                payload_mod
+            )
+        else:
+            self.connect(
+                crc,
+                blocks.repack_bits_bb(
+                    8, # Unpack 8 bits per byte
+                    bps_payload,
+                    self.packet_length_tag_key
+                ),
+                payload_mod
+            )
         self.connect(
-            crc,
-            blocks.repack_bits_bb(
-                8, # Unpack 8 bits per byte
-                bps_payload,
-                self.packet_length_tag_key
-            ),
             payload_mod,
             (header_payload_mux, 1)
         )
@@ -262,7 +282,8 @@ class ofdm_rx(gr.hier_block2):
                  bps_payload=1,
                  sync_word1=None,
                  sync_word2=None,
-                 debug_log=False
+                 debug_log=False,
+                 scramble_bits=False
                  ):
         gr.hier_block2.__init__(self, "ofdm_rx",
                     gr.io_signature(1, 1, gr.sizeof_gr_complex),
@@ -372,7 +393,16 @@ class ofdm_rx(gr.hier_block2):
         payload_demod = digital.constellation_decoder_cb(payload_constellation.base())
         repack = blocks.repack_bits_bb(bps_payload, 8, self.packet_length_tag_key, True)
         crc = digital.crc32_bb(True, self.packet_length_tag_key)
-        self.connect((hpd, 1), payload_fft, payload_eq, payload_serializer, payload_demod, repack, crc, self)
+        self.connect((hpd, 1), payload_fft, payload_eq, payload_serializer, payload_demod, repack)
+        if scramble_bits:
+            descrambler = digital.additive_scrambler_bb(
+                0x8a, 0x7f, 7,
+                bits_per_byte=bps_payload,
+                reset_tag_key=self.packet_length_tag_key
+            )
+            self.connect(repack, descrambler, crc, self)
+        else:
+            self.connect(repack, crc, self)
         if debug_log:
             self.connect((hpd, 1),           blocks.tag_debug(gr.sizeof_gr_complex*fft_len, 'post-hpd'));
             self.connect(payload_fft,        blocks.file_sink(gr.sizeof_gr_complex*fft_len, 'post-payload-fft.dat'))
diff --git a/gr-digital/python/digital/qa_ofdm_txrx.py b/gr-digital/python/digital/qa_ofdm_txrx.py
index adf93ee356..6f5bd2ed10 100755
--- a/gr-digital/python/digital/qa_ofdm_txrx.py
+++ b/gr-digital/python/digital/qa_ofdm_txrx.py
@@ -31,11 +31,11 @@ from gnuradio.digital.utils import tagged_streams
 LOG_DEBUG_INFO=False
 
 class ofdm_tx_fg (gr.top_block):
-    def __init__(self, data, len_tag_key):
+    def __init__(self, data, len_tag_key, scramble_bits=False):
         gr.top_block.__init__(self, "ofdm_tx")
         tx_data, tags = tagged_streams.packets_to_vectors((data,), len_tag_key)
         src = blocks.vector_source_b(data, False, 1, tags)
-        self.tx = ofdm_tx(packet_length_tag_key=len_tag_key, debug_log=LOG_DEBUG_INFO)
+        self.tx = ofdm_tx(packet_length_tag_key=len_tag_key, debug_log=LOG_DEBUG_INFO, scramble_bits=scramble_bits)
         self.sink = blocks.vector_sink_c()
         self.connect(src, self.tx, self.sink)
 
@@ -43,12 +43,12 @@ class ofdm_tx_fg (gr.top_block):
         return self.sink.data()
 
 class ofdm_rx_fg (gr.top_block):
-    def __init__(self, samples, len_tag_key, channel=None, prepend_zeros=100):
+    def __init__(self, samples, len_tag_key, channel=None, prepend_zeros=100, scramble_bits=False):
         gr.top_block.__init__(self, "ofdm_rx")
         if prepend_zeros:
             samples = (0,) * prepend_zeros + tuple(samples)
         src = blocks.vector_source_c(tuple(samples) + (0,) * 1000)
-        self.rx = ofdm_rx(frame_length_tag_key=len_tag_key, debug_log=LOG_DEBUG_INFO)
+        self.rx = ofdm_rx(frame_length_tag_key=len_tag_key, debug_log=LOG_DEBUG_INFO, scramble_bits=scramble_bits)
         if channel is not None:
             self.connect(src, channel, self.rx)
         else:
@@ -113,6 +113,28 @@ class test_ofdm_txrx (gr_unittest.TestCase):
         self.assertEqual(tuple(tx_fg.tx.sync_word2), tuple(rx_fg.rx.sync_word2))
         self.assertEqual(test_data, rx_data)
 
+    def test_003_tx1packet_scramble(self):
+        """ Same as before, use scrambler. """
+        len_tag_key = 'frame_len'
+        n_bytes = 21
+        fft_len = 64
+        test_data = tuple([random.randint(0, 255) for x in range(n_bytes)])
+        # 1.0/fft_len is one sub-carrier, a fine freq offset stays below that
+        freq_offset = 1.0 / fft_len * 0.7
+        #channel = channels.channel_model(0.01, freq_offset)
+        channel = None
+        # Tx
+        tx_fg = ofdm_tx_fg(test_data, len_tag_key, scramble_bits=True)
+        tx_fg.run()
+        tx_samples = tx_fg.get_tx_samples()
+        # Rx
+        rx_fg = ofdm_rx_fg(tx_samples, len_tag_key, channel, prepend_zeros=100, scramble_bits=True)
+        rx_fg.run()
+        rx_data = rx_fg.get_rx_bytes()
+        self.assertEqual(tuple(tx_fg.tx.sync_word1), tuple(rx_fg.rx.sync_word1))
+        self.assertEqual(tuple(tx_fg.tx.sync_word2), tuple(rx_fg.rx.sync_word2))
+        self.assertEqual(test_data, rx_data)
+
     def test_004_tx1packet_large_fO(self):
         """ Transmit one packet, with slight AWGN and large frequency offset.
         Check packet is received and no bit errors have occurred. """
diff --git a/gr-digital/python/digital/qa_scrambler.py b/gr-digital/python/digital/qa_scrambler.py
index 05daebd389..e19e963cd3 100755
--- a/gr-digital/python/digital/qa_scrambler.py
+++ b/gr-digital/python/digital/qa_scrambler.py
@@ -21,6 +21,7 @@
 #
 
 from gnuradio import gr, gr_unittest, digital, blocks
+import pmt
 
 class test_scrambler(gr_unittest.TestCase):
 
@@ -60,5 +61,43 @@ class test_scrambler(gr_unittest.TestCase):
         self.tb.run()
         self.assertEqual(src_data, dst.data())
 
+    def test_additive_scrambler_reset_3bpb(self):
+        src_data = (5,)*2000
+        src = blocks.vector_source_b(src_data, False)
+        scrambler = digital.additive_scrambler_bb(0x8a, 0x7f, 7, 100, 3)
+        descrambler = digital.additive_scrambler_bb(0x8a, 0x7f, 7, 100, 3)
+        dst = blocks.vector_sink_b()
+        dst2 = blocks.vector_sink_b()
+        self.tb.connect(src, scrambler, descrambler, dst)
+        self.tb.connect(scrambler, dst2)
+        self.tb.run()
+        if not (src_data == dst.data()):
+            self.fail('Not equal.')
+        self.assertEqual(src_data, src_data)
+
+    def test_additive_scrambler_tags(self):
+        print 'tags'
+        src_data = (1,)*1000
+        src = blocks.vector_source_b(src_data, False)
+        scrambler = digital.additive_scrambler_bb(0x8a, 0x7f, 7, 100)
+        descrambler = digital.additive_scrambler_bb(0x8a, 0x7f, 7, 100)
+        reset_tag_key = 'reset_lfsr'
+        reset_tag1 = gr.tag_t()
+        reset_tag1.key = pmt.string_to_symbol(reset_tag_key)
+        reset_tag1.offset = 17
+        reset_tag2 = gr.tag_t()
+        reset_tag2.key = pmt.string_to_symbol(reset_tag_key)
+        reset_tag2.offset = 110
+        reset_tag3 = gr.tag_t()
+        reset_tag3.key = pmt.string_to_symbol(reset_tag_key)
+        reset_tag3.offset = 523
+        src = blocks.vector_source_b(src_data, False, 1, (reset_tag1, reset_tag2, reset_tag3))
+        scrambler = digital.additive_scrambler_bb(0x8a, 0x7f, 7, 100, 1, reset_tag_key)
+        descrambler = digital.additive_scrambler_bb(0x8a, 0x7f, 7, 100, 1, reset_tag_key)
+        dst = blocks.vector_sink_b()
+        self.tb.connect(src, scrambler, descrambler, dst)
+        self.tb.run()
+        self.assertEqual(src_data, dst.data())
+
 if __name__ == '__main__':
     gr_unittest.run(test_scrambler, "test_scrambler.xml")